Aircraft are consistently sent to fires too late and miss the opportunity for a hard initial attack, Australia's largest privately-owned helicopter operator says.

"Watching the fire develop when you're sitting with a helicopter ready to go and attack it is a very frustrating exercise," McDermott Aviation president John McDermott told the bushfires royal commission.

Having aircraft available for an immediate response or pre-determined dispatch to locations was best practice around the world, industry representatives told the inquiry on Tuesday.

Philip Hurst, CEO of the national industry body representing aerial firefighting operators and pilots, said there should be pre-determined dispatch of aircraft in a "swarm" or "wolf pack".

South Australia, Victoria and Western Australia already use some form of pre-determined or automatic dispatch.

Mr McDermott said Tasmania was also starting to use the method, which he said was very effective.

Mr Hurst, CEO of the Aerial Application Association of Australia, said having fully-contracted aircraft on standby ready to go and on pre-determined dispatch meant they could be used in an aggressive initial attack role.

"Aggressive initial attack is where aircraft absolutely shine.

"It's where they do their best work when the fire is small and buys time for the ground crews to get in as well as sometimes being able to get the fire out, at least in some significant way, for the ground crews to do a better job."

Mr Hurst said during multi-day campaign bushfires, fire agencies seemed to struggle to get aircraft out before 10am, possibly as they reappraised their attack plan.

"If you were to put those together - pre-determined dispatch for fully contracted aircraft and get them on to the fires as early in the day as possible - we would be able to lift the productivity of the fleet quite considerably without any significant change in expenditure."

National Aerial Firefighting Centre general manager Richard Alder said South Australia was the leader in Australia, if not the world, in introducing a system of automatic dispatch, under pre-determined conditions, in the Adelaide Hills.

"So a fire is reported, the aircraft goes automatically and if it turns out it's not needed, it's turned around," Mr Alder said.

The royal commission was told longer bushfire seasons in the southern and northern hemispheres had not directly impacted the availability of international personnel and resources into Australia.

"We haven't had a situation where the crossing of the seasons or the extending of the seasons has led to non-availability," Australasian Fire and Emergency Service Authorities Council CEO Stuart Ellis said.

Mr Ellis said there were secondary impacts in terms of Australian firefighters possibly not being available for international deployment, if they had not taken leave or had been involved in prescribed burning operations.

AFAC said the 2019-20 bushfire season involved the largest nationally co-ordinated interstate and international deployment of fire and emergency personnel ever mounted in Australia.

More than 7000 interstate and international fire and emergency personnel were deployed into the ACT, Queensland, South Australia, NSW and Victoria.

Australian Associated Press